#include <iostream> 

using namespace std;

double calculation(double a,double b,double (*fuhao)(double x,double y))
{
	return fuhao(a,b);
}

int main()
{
	double a,b;
	cin >> a >> b;
	double res = calculation(a,b,[](double x,double y)->double{return x-y;});
	
	cout << res << endl;
	
	double c;
	cin >> c;
	
	auto res2 = [a,b]()->double{return a+b;};
	double res2_t = res2();
	cout << res2_t << endl;
	
	auto res3 = [=]()->double{return a*b*c;};
	double res3_t = res3();
	cout << res3_t << endl;
	
	auto res4 = [&]()->double{
		a = 10;
		return a*b*c;
	};
	double res4_t = res4();
	cout << res4_t << endl;
	
}
